Halogenated nitriles



HALOGENA'I-ED NITRILES Samuel Allen Heininger, Dayton, Ohio, assignor toMonsanto Chemical! Company, St; Louis, Mo., a corporation of Delaware NoDrawing. Application June 25, 1956 Serial No. 593,314

3. Claims. (Cl. 260-465) This invention relates to halogenated nitriles.and. more. particularly provides diand trihalophenoxypropionitrileswherein the halogen substituent is selected fromv chlorine:

where x represents a halogen atom having amolecular Weight of from 30 to80, i. e., bromine or chlorine and n represents an integer of from 2 to3 Alternatively, a polyhalophenol may be reacted with aS-halopropionitrile, with the formation of products of the aboveformula, and, as'a byproduct, hydrogen chloride.

In preparing the present compounds from acrylonitrile, the desiredpolyhalophenol is contacted with the acrylonitrile at elevatedtemperatures in the presence of an alkaline catalyst and undersuperatmospheric pressure until formation of the desiredhal'ophenoxypropionitrile has occurred; Asshown by the above equation,the desired product is formed by the stoichiometric addition of one moleof the halophenol to one mole of acrylonitrileyaccordingly, the presentreaction is preferably carried out by contacting equimolar quantities ofeach of the said reactants. If desired, an excess of the more readilyavailable reaction component may be utilized. To catalyze the reaction,there is used an alkaline catalyst. Examples of such alkaline catalystsare, e. g., the alkali metals such as sodium or potassium; the oxidesand hydroxides of alkali and alkaline earth metals such as sodiumhydroxide; the alkali alcoholates such as sodium methylate or sodiumethylate; the alkali cyanides such as potassium cyanide, etc.Alternatively, in place of an alkaline salt of an alkali metal, analkaline-reacting organic base such as an amine or, preferably, aquaternary ammonium hydroxide compound may be used. Examples of suitablequaternary ammonium hydroxides are choline(trimethy1(hydroxyethyl)ammonium hydroxide), Triton B(benzyltrimethylammonium hydroxide), acetylbenzyld-imethylammoniumhydroxide, octadecyldiethylmethylammonium hydroxide, etc. Preferably,the alkaline catalyst used in the present reaction is one which issoluble in organic solvents.

If desired, solvents or diluents may be used in the reaction mixture,although it is preferred to dispense with such diluents in the presentreaction so as to avoid problems of concentration of the desiredproduct. Examples of suitable diluents which may be used when desiredare liquid organic compounds which are free of active hydrogen such asdioxane, benzene, hexane, etc. The reaction mixture may also contain apolymerization -in 'ice 2 hibitor, to obviate the possibility ofproducing acrylonitrile polymer during the reaction. Examples of suchinhibitors are, e. g., hydroquinone, the monomethyl ether ofhydroquinone, methylene blue, etc.

To produce useful yields of the present reactionproducts Within feasiblereaction times, the present reaction. of acrylonitrile withapolyhalophenol should be, carried out at elevated temperatures. In.order to maintain-the. present reactants in contact at elevatedtemperatures, it is generally necessary to apply superatmospheric:pressure. Conveniently, the present reaction is carried: out. bycontacting the reactants at elevated temperaturesina: closedpressure-resistant reaction vessel, under the autogenous pressure of thereactants. If desired,v inert. gases.

may be introduced to increase the pressure within, there-n action locus;examples of such gasesare-nitrogen, carbon dioxide, etc. The reaction.temperatures at which. the present reaction proceeds at a desirable rateare of the order of from C. up to below the decomposition; temperaturesof the reactants. Particularly preferablecare: temperatures of from 100to 200 C.

While batch operations are described in the following examples, withsuitable choice of apparatus it is possible to operate the presentprocess continuously, and thereby yields up to quantitative yields maybe obtained. Thus,

e. g., the halophenol and acrylonitrile may be injected into; a heatedtubular reactor wherein a superatmospheric pres-- sure is maintained,the produce halophenoxypropionitrile being isolated from the resultingreaction. product, While:

unreacted acrylonitrile and halophenol are recycledtoundergo furtherreaction.

In an alternative procedure for the synthesis of the present products, apolyhalophenol of the above formula. is contacted with a3-halopropionitrile. In this procedure,

generally equimolar quantities of halophenol and halopropionitrile arecontacted, preferably in the presence of an equimolar quantity of. analkali metal hydroxide. Advantageously, provision is made in carryingout this reaction for the removal of the hydrogen halide formed asbyproduct; thus the alkaline material present, e. g., sodium hydroxide,may also act as a hydrogen halide acceptor. Suitable alkaline catalystsand solvents or diluents for this reaction are as listed above. Thereaction of ahalophenol or an alkali halophenolate with, ahalopropionitrile proceeds readily over a Wide temperature range, andprac ticable reaction rates are generally achieved at relatively" lowtemperatures, e. g., at about 50100 C., with this. reaction. Pressurevariation is generally unnecessary, al: though subor superatmosphericpressures may be employed if desired.

illustrative of the compounds which may be prepared by the presentprocess are, e. g., 2,4-dichlorophenoxypropionitrile,3,4-dichlorophenoxypropionitrile, 2,4,5,-trichlorophenoxypropionitrile,2,6-dichl0rophenoxypropioni-' trile, 2,4,6trichlorophenoxypropionitrile, 2,4 dibromo phenoxypropionitrile,2,4,S-tribromophenoxypropionitrile, 3,5-dichlorophenoxypropionitrile,2-chloro-4-bromophenoxypropionitrile, etc.

The present compounds are for the most part solid crystalline materialshaving a relatively low melting point, below 100 C. They may be used fora variety of chemical and industrial purposes. Thus, for example, theuse of the present compounds as nematoci-des is disclosed inaforementioned copending application Serial No. 476,602, filed December20, 1954. I have also discovered that the present compounds possessuseful fungicidal, arachnicidal, and phytocid-al properties. inparticular, it has been found that the present polyhalophenolsunexpectedly possess fungicidal properties as a foliage protectant whichare not shared by the monohalogenated compounds of similar structure.Furthermore, the compounds of the in- Patentedv J an- 7, 1958.-

Example 1 A mixture of 489 g. (3.0 moles) of 2,4-dichlorophenol, 3 g. ofsodium methylate and 160 g. (3.0 moles) of acrylonitrile was placed in aone-liter autoclave which was closed, heated to 150 C., and rocked for12 hours. After acidification with concentrated hydrochloric acid, thereaction mixture was distilled: the unreacted acrylonitrile recovered inthe distillation weighed 127 g.; recovered phenol weighed 400 g. The potresidue (boiling above 195/0.5 mm. pot temperature) was treated with 300ml. of ether and 200 ml. of 10% sodium hydroxide, and the mixturefiltered to remove tar. The ether layer was separated and washed with100 ml. of 10% sodium hydroxide solution and then washed three timeswith 100 ml. portions of water. After drying over sodium sulfate, theether was evaporated off, whereby there were obtained 30 g. of3-(2,4-dichlorophenoxy)pro pionitrile, M. 54-56 C. afterrecrystallization from an ethanol-water mixture.

Example 2 By refluxing a mixture of 200 g. (0.8 mole) of2,4,-dibromophenol, 89.5 g. (1.0 mole) of 3-chloropropionitrile, and 200ml. of 30% KOH for 4 hours, 3-(2,4-dibromophenoxy)propionitrile isprepared. This product, after isolation by distillation, may beidentified by conversion to the corresponding acid, e. g., byhydrolyzing the nitrile with hydrochloric acid.2,4-dibromophenoxypropionic acid melts at 115-116 C.

Example 3 Using the procedure of Example 2, by the reaction of2,4,5-trichlorophenol with acrylonitrile there may be prepared3-(2,4,S-trichlorophenoxy)propionitrile.

Example 4 This example describes the evaluation of3-(2,4-dichlorophenoxy)propiontrile as a fungicide, and a comparison ofthe fungicidal properties thereof with those of3-(2-chlorophcnoxy)propionitrile and 3-(4-chlorophenoxy)propionitrile.

3-(4-chlorophenoxy)propionitrile was prepared by refluxing a mixture of384 g. of p-chlorophenol with 212 g.

(4.0 moles) of acrylonitrile containing 5 g. of hydroapproximately 24hours; there were obtained 89 g. of 3-(2- chlorophenoxy)propionitrile,B. 111-113 C./0.25 mm., melting point after recrystallization, 46-47 C.

Emulsions of the 3-(2-chlorophenoxy)-, 3-(4-chlorophenoxy)-, and3-(2,4-dichlorophenoxy)propionitriles synthesized as described abovewere prepared by mixing samples of acetone solutions of thepropionitriles with an emulsifying agent known as Tween 20 and reputedto be a polyalkylene glycol derivative of sorbitan monolaurate, andadding water thereto. The emulsions were sprayed on Bonny Best varietytomato plants which were about 3 to 5 inches tall and each had at least4 true leaves. After being held two days on a greenhouse bench, theplants were placed in a moist chamber at F. and sprayed with a sporesuspension of Stemphylium solani, the fungus responsible for animportant leaf blight disease of tomatoes. After 3 days incubation, theplants were removed to the greenhouse bench, Where they were inspected 2days later, the extent of infection of the plants being judged bycounting leaf lesions, with reference to an inoculated, untreatedcontrol plant and to an inoculated plant treated with a commercialreference fungicide. It was found that substantially complete repressionof the fungus infestation, equal to that obtained by application of thecommercial reference fungicide, was obtained on the plants sprayed withan emulsion containing 625 parts per million of3-(2,4-dichlorophenoxy)propionitrile. By contrast, leaf-spot equal tothat of the untreated control was observed with tomato plants treatedeven with emulsions containing twice as high a concentration, 1250 partsper million, of either 3-(2-chlorophenoxy)- or3,(4-chlorophenoxy)propiontrile.

While the invention has been illustrated with particular reference tovarious individual embodiments thereof, it will be obvious that othervariations may be made within the scope of the present invention.

What is claimed is:

1. A polyhalophenoxypropionitrile of the formula Q0 cramnon where X is ahalogen atom having a molecular weight of from 30 to 80, and n is aninteger of from 2 to 3.

2 3-(dichlorophenoxy)propionitriles.

3. 3-(2,4-dichlorophenoxy)propionitrile.

References Cited in the file of this patent UNITED STATES PATENTS2,421,837 Hardman June 10, 1947 2,733,257 Barber et a1 Jan. 31, 1956FOREIGN PATENTS 670,357 Germany Jan. 17, 1939 OTHER REFERENCES Newman etal.: J. A. C. S., vol. 69, pp. 718-20 (1947).

1. A POLYHALOPHENOXYPROPIONITRILE OF THE FORMULA